Ion implanters may employ detector to measure and tune the uniformity of an ion beam as the ion beam is directed to a substrate at an end station. Often a detector in the form of a current monitor, such as a Faraday cup is placed in a beamline in or near the end station, where a substrate is processed. In ion implanters employing a scanned spot beam, the ion beam may be measured in more than one manner. In one mode of measurement, which mode may be deemed a stationary slow spot beam profile, a beam scanner is turned off so an undeflected ion beam passes through the beam scanner and projects onto a substrate plane (wafer plane), often at a position of 0 mm, meaning a center of the wafer. A detector, such as a Faraday detector is scanned across the wafer plane to measure the stationary ion beam, generating measurements of the spot beam size, beam shape, and so forth, for a scan taking 10 seconds, for example, for a 300 mm wafer. In another mode, which mode may be deemed a scanned linear profile, the net result of the ion beam density across the wafer plane is measured as the ion beam is scanned back and forth at a constant velocity, such as 1000 Hz, where the velocity may match the scanning velocity of a scanned spot beam to be employed during wafer processing. While the ion beam is being scanned at this high velocity, a detector, such as a Faraday detector, may be scanned at 30 mm/second across the wafer plane to measure the stationary spot beam shape, size etc. In an additional mode, which mode may be deemed a stationary fast spot profile, a detector is located at a stationary position, such as 0 mm (wafer center) while the ion beam is rapidly scanned across the detector for several cycles, such as 5-16, creating an average spot beam profile in approximately 10 msec. In cases where the spot beam and ion implanter operate in an ideal manner, there would be no change in a spot beam across the wafer plane and these three approaches can be used by the operator visually diagnose and correct for up-stream ion beam scanning and focusing issues. Notably, if the spot beam shape or position changes significantly across the wafer plane as the spot beam is being scanned, these three approaches do not provide the operator with sufficient visual tools to properly diagnose and correct for upstream scanning and focusing issues.
Notably, as beam energies become lower and lower, the spot beam changes more and more across the wafer plane, which changes cause non-uniformities in the ion beam density, where the non-uniformities are hard to correct. This inability for the operator to visually discern and correct non-uniformities in scanned spot beams ultimately can reduce the yield and degrade the performance of the semiconductor devices.
It is with respect to these and other considerations the present embodiments are provided.